DANU (pronounced DAH-noo) is the Irish earth Goddess, mother of the Tuatha D'e Danann (people of the Goddess Danu). Danu is an ancient Goddess, and was worshipped extensively throughout Western Europe, ruling over rivers, magic, fertility, wells, and wisdom. She gives her name to many European places, including the Danube River and the country of Denmark. Danu, whose name means "wisdom", was known as DON in Wales, and her name is also seen as DANA or DANANN.

The Tuatha D'e Danann (pronounced TOO-uh-huh dey DAH-nun) were the fifth group to inhabit Ireland. After learning the magical arts, they arrived in Ireland on ships, which they then burned so that they would not be tempted to go back to where they had come from. They defeated the Fir Bolg (pronounced FEER buhl-ug) who then inhabited Ireland, and were the main population until the arrival of the Milesians. The Milesians nearly wiped out the Tuatha D'e Danann--the survivors were driven to T'ir na n'Og (pronounced TEER na nohg), the "land of eternal youth", or underground, where they took the name Daoine S'idhe (pronounced DEEN-uh SHEE) or "people of the mounds". There they continue to reside, and we know them better as fairies.